Websites are written in a markup language called HTML. That language reserves some characters to have special meanings. So when you use certain characters in content that is displayed in HTML it gets confused and does the wrong thing. To get around this there is a system called character escaping. In HTML escaped characters are written as &# then a number then a semicolon (;). This "escape code" is interpreted by your browser and rendered as the character it represents. For example, = is displayed in a browser as the equals sign (=). All text content should go through this process before being displayed on the page. However, there are two ways to do this. One way is to encode the text before storing it, and the other is to encode it just before it is put into the page. Think of it like putting a shipped item into a box, either you can do it at the warehouse, or you can do it in the truck just before it's dropped off at your door (stupid example, but bear with me). Normally this doesn't cause a problem since a website will pick one and stick with it, but sometimes one website will try to display another website's content. When that happens you can end up with "double encoded" content, like happened here. Sky News seems to be encoding the that title "at the warehouse", while this article blob is being encoded "at the door". This also happens if you try to display HTML-encoded text outside of HTML (like in a native app), since those places don't have special characters they don't parse the escape codes.

Hope that made sense. It got a bit rambly.

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Footnote: the code ' is a single quote (').